1. Field of the Invention
The present invention relates to a screening apparatus comprising an elongated support frame; a mobile, deformable sieve consisting of a sieve mat and having lateral edges extending in the direction of the length of the support frame; and a series of alternatingly immobile and mobile sieve mat carriers mounted on the support frame along the length thereof, the sieve mat being affixed to the carriers and the mobile carriers being movable with respect to the support frame in the direction of the length of the support frame.
2. Description of the Prior Art
Austrian Patents Nos. 386,137 and 387,342 disclose screening apparatus in which seals are arranged between the sieve mats and adjacent side walls of the support frame to prevent coarse grains from penetrating below the sieves. Such gliding seals always constitute a weak point in the screening apparatus. In addition to the wear of the seals, the required changes of the sieves cause malfunctions because of the necessary accurate fit.
In other known screening apparatus of this general type, finely porous, elastic materials affixed to the support frame side walls are used as seals between the sieve mats and the adjacent support frame side walls. Because of the rapid destruction of such sealing materials by the goods being sifted, such screening apparatus has an unacceptably short operating life.